Effect of pyrolysis temperature and feedstock type on agricultural properties and stability of biochars.

Pyrolysis temperature and feedstock type used to produce biochar influence the physicochemical properties of the obtained product, which in turn display a range of results when used as soil amendment. From soil carbon (C) sequestration strategy to nutrient source, biochar is used to enhance soil properties and to improve agricultural production. However, contrasting effects are observed from biochar application to soil results from a wide range of biochar?s properties in combination with specific environmental conditions. Therefore, elucidation on the effect of pyrolysis conditions and feedstock type on biochar properties may provide basic information to the understanding of soil and biochar interactions. In this study, biochar was produced from four different agricultural organic residues: Poultry litter, sugarcane straw, rice hull and sawdust pyrolysed at final temperatures of 350°C, 450°C, 550°C and 650°C. The effect of temperature and feedstock type on the variability of physicochemical properties of biochars was evaluated through measurements of pH, electrical conductivity, cation exchange capacity, macronutrient content, proximate and elemental analyses, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses. Additionally, an incubation trial was carried under controlled conditions to determine the effect of biochar stability on CO2-eq emissions. Results showed that increasing pyrolysis temperature supported biochar stability regardless of feedstock, however, agricultural properties varied widely both as an effect of temperature and feedstock. Animal manure biochar showed higher potential as nutrient source rather than a C sequestration strategy. Improving the knowledge on the influence of pyrolysis temperature and feedstock type on the final properties of biochar will enable the use of better tailored materials that correspond to the expected results while considering its interactions with environmental conditions

Studio dell'alterazione cromatica di materiali lapidei nell'area cittadina di Aosta: un approccio multianalitico

Il progetto presentato parte dalle attività svolte dalla Direzione ricerca e progetti cofinanziati per lo studio conservativo del Teatro romano di Aosta, prendendo come punto chiave le alterazioni cromatiche (definizione NORMAL 1/88: variazione naturale a carico dei componenti della pietra dei parametri che definiscono il colore)1 cui è soggetta la puddinga, un conglomerato di origine fluviale, impiegata dai Romani per l’edificazione della città e, in particolare, per la Porta Prætoria, una delle quattro porte che permettevano l’accesso alla città romana. L’obiettivo principale dello studio è l’individuazione di una correlazione fra le alterazioni cromatiche della puddinga e l’ambiente, per evidenziare i processi che portano alla variazione dei parametri che definiscono il colore (tinta, saturazione, luminosità), con scopo ultimo la definizione di un piano di conservazione per il monumento